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Planting of Atlantic salmon eggs in Kennebec River starting to pay dividends; over the past four years, more wild adult salmon are returning to the hatching grounds.

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Planting of Atlantic salmon eggs in Kennebec River starting to pay dividends; over the past four years, more wild adult salmon are returning to the hatching grounds.

salmon recovery, egg planting, Kennebec River

Paul Christman has found that over the past four years, more wild adult salmon are returning to hatching grounds. Staff photo by Jill Brady

MADRID — Paul Christman held his walking stick to steady himself as he looked into the Sandy River and waded up stream. Anyone watching from the bank might think he was a fly fisherman who lost his rod.

Christman was walking in the frigid mountain stream in mid-November not to fish but to find Atlantic salmon spawning beds – or redds – so a multi-agency team of biologists can plant Atlantic salmon eggs this winter.

It will mark the 10th year Christman’s team has planted eggs in the Sandy River – a tributary of the Kennebec in Franklin County. Over the past four years Christman has cataloged more adult salmon returning to the Kennebec from the species’ migration run to Greenland.

Atlantic salmon were first listed as threatened by the U.S. Fish and Wildlife Service in 2000 in a small portion of Maine. In 2009 the list was expanded and the salmon’s status was elevated to endangered.

The effort to recover the species is being conducted by the U.S. Fish and Wildlife Service, the National Oceanic and Atmospheric Administration, and Christman, a biologist with the Department of Marine Resources.

“This past summer was our fourth summer of adults returning, and this summer was our best adult returns with 40,” Christman said.

Since 2010 as many as 300,000 to 1 million Atlantic salmon eggs grown in a hatchery have been planted, or seeded, in the river in places Christman and his team believe an adult female salmon would select to spawn.

The fry salmon that emerge from the eggs grow in the river for four years before going to sea on a migration run. Christman said the salmon that emerge from the planted eggs are wilder than hatchery-grown Atlantic salmon stocked in other rivers as adults. And the wilder the fish introduced in the river, the better the chance of survival.

Atlantic salmon have spawned in Maine rivers and migrated to Greenland for tens of thousands of years. Yet scientists know little about what happens to them after they leave the Gulf of Maine.

“If they emerge in the wild there is more natural selection and the fry are likely in developmental sync with the environment,” Christman said.

After four years of adult returns in the Sandy River, Christman believes the project has the potential to produce a naturally occurring salmon population in the crystal-clear mountain river.

“You can see the salmon in here,” Christman said as he walked in the knee-deep water. “That makes the Sandy unique. This is the only place in the U.S. where wild adults can be seen.”

In 2014, biologists recorded fewer than 20 returning adults in the Kennebec River. They counted 29 returns in 2015, 39 in 2016 and 40 this year.

Those numbers do not represent all the adult salmon that have returned to the Kennebec – only those caught at Lockwood Dam in Waterville. But Christman is encouraged the numbers continue to go up.

Four dams remain in the Kennebec that block the way for the returning adult salmon, so Christman and his team wait at the Lockwood Dam in the summer to catch and move salmon up river to the Sandy.

In the late fall, biologists search the Sandy for spawning beds made by wild adult salmon to assure the hatchery eggs are planted far from wild eggs. The idea is to maximize the success of both types of eggs.

The team walked miles of the Sandy River looking for rock structures in the river where the velocity of the water picked up.

In these spots there is more oxygen in the water, and often places with eggs laid by wild salmon. A subtle depression of gravel that is three feet long is clearly a wild salmon bed, said biologist Jake Overlock.

Christman said the salmon are fussy in choosing their spawning sites to assure success.

“Location, location, location,” he shouted from the river.

The Sandy isn’t the only river in Maine where hatchery-grown eggs are planted. Marine Resources also has planted salmon eggs in the Sheepscot and Penobscot rivers, the Downeast Salmon Federation has in the Machias, Pleasant and Narraguagus rivers, and the Saco River Salmon Restoration Alliance has in the Saco.

Graham Goulette, a fisheries biologist with NOAA who is on Christman’s team, said the goal in the Sandy is to plant enough eggs to produce a self-sustaining population, but the other piece of Atlantic salmon recover is marine survival.

A study using acoustic transmitters affixed to salmon leaving the Kennebec in 2014 and 2015 showed Goulette the salmon make it as far as Halifax, Nova Scotia. But that’s where the research ends because of a lack of receivers in the North Atlantic.

“Beyond that it’s following a needle in a haystack,” Goulette said of scientists’ understanding of the fish’s migration journey.

Goulette said there’s little scientists can do to help salmon survival in the open ocean, but egg-planting by biologists remains essential.

“If you gave up the freshwater aspect, then you wouldn’t have anything,” he said.